The first unit is the arithmetic concept of mathematics, which is a standard quantity. There is no formal definition, only a descriptive definition that widely exists in the practice of fraction teaching, so invariants are generally chosen as unit one.

Explain in detail:

The unit 1 refers to a whole conceptual unit 1. This problem will be applied to many mathematical problems. In mathematics, the unit 1 refers to a whole concept. For example, in the problem, we don't know how long a certain amount and a certain time are, so we can regard this amount and this time length as the unit of 1.

It is worth noting that the unit 1 will never change as a whole. We just regard it as a whole, not that it is only 1 copy.

For example, now that we don't know the construction amount, we will say that the total amount of this construction is 1. If Team A has completed the construction for 6 hours, then we divide the total amount by 6 with the unit 1, and we can get that the efficiency of Team A is 1/6.

For another example, we don't know how many pages a book has, so we regard it as a unit of 1. It is understood that Xiao Li finished reading this book in 8 hours. Then, by dividing the integer of 1 by the speed of 8 hours, we can get that his reading speed is 1/8.

Arithmetic concept, also known as integer "1". There is no formal definition, only a descriptive definition widely existing in the practice of fraction teaching: a complete quantity (such as a distance, an item, a basket of apples, a book, a period of time, etc. ) or a number (positive number) is regarded as a whole or a unit, and the natural number is given the characteristic of 1, which can be recorded as "1".

Mathematical significance:

1, the unit of the original quantity, (refers to a small quantity that constitutes the original quantity, such as a distance of 3 hours, and the average distance traveled per hour is a unit of one distance. ) or the unit of a number can be converted into a smaller unit than "1", so there is a definition of fraction: divide unit one (or the whole "1") into several parts on average, indicating that one or more of them are fractions.

2. You can redefine another quantity with the same unit as the original quantity with the unit of "1" and express it with a fraction. This score is often called the corresponding score of another quantity.